textproduct: Quad Cities

KEY MESSAGES

- Dense fog will be found across parts of the area early this morning.

- A cold front will bring scattered showers and thunderstorms (30-50% coverage) to the area late this afternoon into the overnight hours. A few of these storms could be severe with the primary hazards being gusty winds and locally heavy downpours. - An active pattern keeps rain chances on the table through the middle of next week with plenty of dry hours in between, but muggy to oppressive humidity returns.

SHORT TERM /THROUGH SATURDAY NIGHT/

Issued at 116 AM CDT Fri Aug 7 2026

Another morning of dense fog ahead with storm chances returning this afternoon and evening. A shortwave trough and an accompanying surface boundary is forecasted to swing in from the northwest with isolated to scattered (30-50%) storm coverage due to the positive tilt of the troughs limiting low-level WAA and mid-level moisture advection. In addition, subsidence ahead of the weak cold front will lead to 50-100 J/kg of SBCIN, inhibiting widespread convective initiation. That being said, latest CAM guidance is hinting that convection further upstream in southern Minnesota could organize into an MCS, propagating southeastward towards our CWA during the late afternoon. Due to the factors listed above and only modest instability in the form of 1000-1750 J/kg of SBCAPE, maintenance of any convection is unlikely. The SPC does have a Marginal Risk (Level 1 out of 5) for severe wind gusts west of a line between Keokuk, IA and Dubuque, IA, but this threat is conditional on convection even developing.

Heading into tonight, the trough clears the area as a weak high pressure takes its place. Northwesterly flow and CAA behind the front should allow lows to drop into the 60s and skies to clear. Dry conditions are expected to persist through the day on Saturday with seasonable highs in the low-to-mid-80s.

Enjoy the dry, mild conditions while you can before they disappear once again Saturday night. A couple shortwaves, one over the Central Plains and another on the backside of the longwave trough near Hudson Bay, are forecasted to deepen a low pressure along the Front Range in Colorado and Wyoming and push a weak surface trough into the Great Lakes region. These two lobes of low pressure are likely to form a low-level deformation zone over Minnesota and Iowa, enhancing the low-level WAA and convergence over the region and bringing PoPs back up (50-70%). While it is difficult to determine the severity of convection due to this event being nocturnal and potentially elevated with a developing warm front, the SPC does highlight a Marginal Risk (Level 1 out of 5) for severe storms in the southwest quarter of our CWA where a developing LLJ could support some convective organization and damaging winds.

LONG TERM /SUNDAY THROUGH THURSDAY/

Issued at 116 AM CDT Fri Aug 7 2026

Sunday-Monday...As the two shortwaves quickly move to the southeast, the deformation zone remain in place Sunday, but PoPs should decrease to 30-50% with the lack of upper-level dynamical support. The low pressure over the Central Plains is also expected to stall out which will be an issue heading into Sunday night as another subtle shortwave zooms across Wyoming into South Dakota and Nebraska. A second LLJ is likely to develop, spawning another round of showers and storms Sunday night into Monday. This shortwave trough will also reinvigorate the deformation zone and pull it northward. The increased southwesterly flow, low-level WAA, and moisture advection could lead to excessive heat developing, especially in our south where clearing skies are more likely. Current LREF guidance has a 20-30% chance of heat indices exceeding 100 degrees south of Interstate 80 Monday afternoon. Regardless though, dew points are going to be in the 70s, possibly in the mid-to-upper 70s (40-60% chance per 06.12z LREF guidance), making it feel muggy to oppressive outside even with potential cloud cover.

Tuesday-Thursday...Multiple shortwaves passages will keep precipitation chances around through the middle of next week, but these repeated passages should slowly push the deformation zone further south as high pressure eventually settles back in over the region. There is general consensus among the ensembles that a return to north-to-northeasterly flow in the low-levels should erode away at the high dew points and temperatures, returning to the area to seasonable conditions by the end of next week.

AVIATION /12Z TAFS THROUGH 12Z SATURDAY/

Issued at 634 AM CDT Fri Aug 7 2026

Fog will impact KCID, KDBQ, and KBRL at the start of the period with IFR to VLIFR conditions improving to VFR by 14-15z. Later this afternoon and evening there will be a chance for showers and storms ahead of a weak cold front. There is uncertainty though with the coverage and strength of storms, as a possible scenario is that the greater instability and bulk of storms stay mainly west of the terminals. Will continue to keep PROB30 tsra mention at KCID and KDBQ 23z-02z, as not confident either way to make any changes at this time. Any showers/storms should be weakening if they were to approach KMLI and KBRL in the evening. Winds will turn westerly or light as the weak boundary sags into the area tonight. Some fog will be possible again, but too low of confidence to add mention with 12z. Otherwise, more upper level wildfire smoke is expected during the period.

DVN WATCHES/WARNINGS/ADVISORIES

IA...Dense Fog Advisory until 9 AM CDT this morning for IAZ040>042- 051>053-063>065-076-077-087-098. IL...None. MO...Dense Fog Advisory until 9 AM CDT this morning for MOZ009.